After adding this from Add Widget, the RSS Feed button is not ghosted. This also creates a problem if Widget Manager is used. The expected behavior is that if RSS Feed Widget has been added to the profile page the button should be ghosted. Please see picture

@ura soul, it looks like files were changed on the guy's server. On a properly configured server that should not be possible. This has nothing to do with Elgg accounts or connecting to mysql.
1. The web server user should not be able to write to... view reply

Twitter has created new display requirements. That is issue #1. The have also turned off unauthenticated access to tweets. That is issue #2. There are two ways to get tweets:
Use the API (with authentication) to grab tweets and then build a... view reply

Elgg 1.8.16 has been released to address a flaw with avatar handling. Thanks to Jerôme Bakker of ColdTrick for discovering and reporting this issue to us.
Keep your Elgg site running smoothly by upgrading today.
Other bug fixes...

If it's only the verification emails that fail to receive the users, you can try changing the wording within the email body to see if it helps. But I won't expect too much of this - it might help on short term but the spam filters of the email providers will learn and you will have the same problem again at some time in future (rather sooner than later). Also, changing anything in the email header seems not promising to me - after all the other notification emails do reach their destination, so it's not a general problem with the email header.

The most promising point is "server is not trusted". There are ways to improve the credibility of your server but it depends on your server config, if you can use them. You mentioned in another thread that you use the PHP mailer plugin to send the emails from your Elgg site via Gmail. In this case you have no change to improve the credibility of your server because the emails are sent via Google and you can't influence the credibility. Instead you would need to use your own mail server on your own server (or webspace). Do you host your site on some webspace? In case you do, you can ask your hoster about ways to improve credibility, e.g. using the SPF framework, domain keys and setting up a valid PTR record.

As per your suggestion I have changed the content of the verification email and now users are receiving the emails and this happened after I deactivated "PHPmailer" plugin. But, I am afraid as this is only a temporary solution.

Have even asked Godaddy support team to resolve the issue and am waiting for their revert.